This term came about through a very popular cartoon of a helmet topping off a pair of boots to signify the veteran with just a short time left in his enlistment and keeping a REALLY low profile, turtle-like, trying to make it out alive. Among VietNam and older veterans a challenge term by which infantrymen recognized each other.

When a veteran infantryman would meet another veteran, the question would be asked: "Are you a turtle?". To which the challenged veteran would have to either reply "You bet your sweet ass I am!" or have to buy the challenging veteran a drink.

Turtles are reptiles of the order Testudines, most of whose body is shielded by a special bony or cartilaginous shell developed from their ribs. "Turtle" may either refer to the Testudines as a whole, or to particular Testudines which make up a form taxon that is not monophyletic.